The goals of this study are to better characterize Autistic Spectrum Disorders (ASD) and social communication problems in low birthweight (LBW) survivors and to better understand the relation between pre, peri and neonatal complications, including brain injury to ASD and social and communication problems in this population. The study sample will be drawn from the Neonatal Brain Hemorrhage Study (NBHS) cohort, the largest regional LBW cohort screened with serial cranial ultrasound (US) ever to be assembled. The cohort was re-assessed at age 15-16 and parent report on screens for ASD (Social Communication Questionnaire and the Asperger Syndrome Screening Questionnaire) was obtained. We propose to rigorously evaluate for diagnosis all participants who screened positive for ASD and a sample of those who screened negative. The specific aims pursuant to this goal are: (1) to estimate, for this LBW population, the current prevalence of ASD and to compare this prevalence to those reported in general populations studies; (2) to systematically describe and compare, based on ASD screening status, the phenomenology and developmental history of those positive for an ASD diagnosis (ASD True Positives), those positive on the ASD screen but not diagnostically positive for ASD (ASD False Positives) and those who were negative on the ASD screen as adolescents and negative for ASD upon diagnostic evaluation as well (Controls). The domains described and compared will include both the core domains affected in ASD (social interaction, communication and interests) and associated features (cognition, motor function, adaptive behavior, minor physical anomalies) (3) to examine predictors of ASD true positives and separately, predictors of ASD false positives using the extensive set of specific pre-, peri- and neonatal complications available from the original NBHS study; including indices of maternal infection and cranial US evidence of white matter injury (4) to examine the relation of family loading for psychiatric disorder to ASD true positive status and ASD false positives status, (5) to estimate, for this LBW population, the screening properties of the SCQ and the ASSQ for ASD true positives, ASD false positives and controls. This application has the potential to yield important information about ASD and social and communication problems in LBW survivors. In addition to describing the prevalence and presentation of ASD in LBW survivors, it will elucidate etiologic mechanisms that may inform prevention and treatment of ASD and social and communication problems in the general population. [unreadable] [unreadable]